Device with wavelength selective coupler for collecting light emitted by a laser source

Abstract

A device for collecting light emitted by a laser source, including an optical wave guide arranged so as to collect a light signal emitted by the laser source, by coupling. The wave guide includes a loop coupled to a laser source in two coupling zones making it possible to recover optical modes circulating along the direction opposite to the required direction for the signal output from the device.

The invention claimed is: 
     
       1. A device comprising:
 a laser source; and 
 a continuous optical wave guide that collects a light signal emitted by the laser source by coupling, 
 wherein the light signal is emitted by the laser source in at least two distinct zones, 
 the wave guide comprises a part configured to transport the light signal output from the device and a part forming a loop that collects the light signal emitted by the laser source in at least two coupling zones by coupling, the loop being separated from the laser source at the coupling zones by a material with a low refraction index, 
 the loop comprises a first segment prolonged by a second segment prolonged by a third segment, the second segment connecting the first coupling zone of the loop to the second coupling zone of this loop, 
 the first and third segments, as junction segments, connect the second segment to the first and second inputs respectively of a two-to-one coupler, an output of which is connected to a fourth segment forming the part configured to transport the light signal output from the device, 
 the second segment includes an optical path configured so that there is interference in each of the coupling zones, between a part of the light signal captured at one of the coupling zones and transported by the corresponding junction segment, and a part of the light signal captured at another coupling zone and transported by the second segment, and 
 optical paths of the first and third segments are configured so that there is interference in the two-to-one coupler between signals transported by the junction segments. 
 
     
     
       2. A device according to  claim 1 , in which the loop surrounds the laser source. 
     
     
       3. A device according to  claim 1 , in which a shape of the loop is symmetric. 
     
     
       4. A device according to  claim 1 , further comprising means for controlling the optical path of at least part of the loop. 
     
     
       5. A device according to  claim 1 , in which the two-to-one coupler is a Y coupler. 
     
     
       6. A device according to  claim 1 , in which the coupling zones are isolated. 
     
     
       7. A device according to  claim 1 , in which a shape of the loop is partly symmetric. 
     
     
       8. A device according to  claim 1 , in which a shape of the loop is asymmetric. 
     
     
       9. A device according to  claim 1 , in which the two-to-one coupler is a multimode interferometric (MMI) coupler.